That God preserves things in being

FROM God's governing all things by His providence it follows that He
preserves them in being.* For everything
whereby things gain their end is part of the governing of them. But to
the last end which God intends, namely, the divine goodness, things are
directed not only by their activities, but also by the fact of their
existence, because by that mere fact they bear some likeness to the
divine goodness. Therefore it is proper to divine providence to keep
things in being.

5. As a work of art presupposes a work of nature, so a work of nature
presupposes a work of God creating: for the material of artificial
things is from nature, and the material of natural things is through
creation of God. But artificial things are preserved in being by virtue
of natural things, as a house by the solidity of its stones. Therefore
natural things are not preserved in being otherwise than through the
power of God.*

6. The impression made by an agent does not remain in the effect when
the action of the agent ceases, unless that impression turns into and
becomes part of the nature of the effect. Thus the forms and properties
of things generated remain in them to the end, after the generation is
done, because they are made natural to the things: in like manner
habits are difficult to change, because they turn into nature. But
dispositions, bodily impressions, and emotions, though they remain for
some little while after the action of the agent, do not remain
permanently: they find place in the subject as being on the way to
become part of its nature.* But what belongs
to the nature of a superior genus in no way remains after the action of
the agent is over, as light does not remain in a transparent medium
after the source of light is taken away.* But
being is not the nature or essence of anything created, but of God
alone (B. I, Chapp. XXI, XXII). Nothing then can remain in being when the
divine activity ceases.*

7. Concerning the origin of things there are two theories, one of
faith, that things had a first commencement, and were then brought into
being by God; the other the theory of sundry philosophers, that things
have emanated (fluxerint) from God from all eternity. On either
theory we must say that things are preserved in being by God. For if
things are brought into being by God after not being, the being of
things must be consequent upon the divine will; and similarly their not
being, because He has permitted things not to be when He willed and
made things to be when He willed. Things therefore are, so long as He
wills them to be. His will then is the upholder of creation. On the
other hand, if things have emanated from God from all eternity, it is
impossible to assign any time or instant in which first they emanated
from God. Either then they were never produced by God at all, or their
being is continually coming forth from God so long as they exist.

Hence it is said: Bearing up all things by the word of his power
(Heb. i, 3). And Augustine says (De Gen. ad lit. iv, 12): "The
power of the Creator, and the might of the Almighty and All-containing,
is the cause of the permanence of every creature. If this power ever
ceased from governing creation, all the brave show of creatures would
at once cease, and all nature would fall to nothing. It is not like the
case of one who has built a house, and goes away, and still the
structure remains, when his work has ceased and his presence is
withdrawn. The world could not endure for the twinkling of an eye, if
God retired from the government of it."

Hereby is excluded the theory of some Doctors of the Law of the Moors,
who, by way of sustaining the position that the world needs the
preserving hand of God, have supposed all forms to be accidents,* and that no accident lasts for two successive
instants, the consequence being that the formation of things is always
in the making, -- as though a thing needed no efficient cause except
while it is in the making. Some of them are further said to hold that
the indivisible atoms,* out of which they say
that all substances are composed, -- which atoms, according to them,
alone are indestructible, -- could last for some short time, even
though God were to withdraw His guidance from the world. Some of them
further say that things would not cease to be but for God causing in
them an accident of 'ceasing.'* All which
positions are manifestly absurd.